1. Field of the Invention
The present invention relates to a microwave oven, and more particularly, to a heating apparatus of a microwave oven for supplying a heat source other than microwave to a cooking chamber.
2. Description of the Background Art
In general, a microwave oven generates microwave by using electricity. As the microwaves infiltrate into a cooking object, a movement of molecules is made in the cooking object, according to which the food stuff is heated.
In case of the currently used microwave oven, since there is a limitation in the to use of only microwaves as a heat source for heating foodstuff, a heating apparatus is additionally installed to heat foodstuff by using a heating source other than microwave.
FIG. 1 is a view showing the construction of a microwave oven having a heat apparatus in accordance with conventional art.
The conventional microwave oven includes: a cooking chamber 102 for receiving a cooking object; a tray 104 installed at a lower portion of the cooking chamber 102, being rotated with foodstuff placed thereon; a magnetron (not shown) mounted at one side of the cooking chamber 102, for generating microwaves for heating foodstuff; and a heating apparatus for providing a heat source (other than microwave) required for heating foodstuff generated from the magnetron.
The heating apparatus includes a heater 106 disposed at an upper portion in a cooking chamber 102, a ventilating fan 108 disposed at the center of the heater 106, for circulating air inside the cooking chamber 102 to pass across the heater 106; and an upper plate 116 installed at a certain position of an upper side of the cooking chamber 102, in which the ventilating fan 108 and the heater 106 are inserted, and having a plurality of holes for passing air.
The upper plate 116 includes suction holes 120, through which air inside the cooking chamber 102 is introduced into a circulating chamber 112, formed at the center thereof and discharge holes 120 formed in a circumferential direction, for supplying air that is heated while passing across the heater 106 into the cooking chamber 102.
As stated above, in the heating apparatus of a microwave oven, when the ventilating fan 108 is driven, air from the cooking chamber is supplied through the suction hole 120 to the heater 106 and the air heated while passing across the heater 106 is supplied through the discharge hole 120 to the cooking chamber 102, thereby heating foodstuff.
In this manner, the heating method of the heating apparatus of a conventional microwave oven adopts the air convection method in which the air inside the cooking chamber 102 is drawn into the upper central portion of the cooking chamber 102 and supplied through the upper marginal portion of the cooking chamber 102.
However, the conventional heating apparatus of a microwave oven as described above has the following problems.
That is, since it indirectly heats foodstuff according to an air circulation method wherein as the ventilating fan is driven, the air inside the cooking chamber is heated while passing the heater, and the heated air is supplied to the cooking chamber to heat foodstuff, there is much heat loss and its heating efficiency is degraded.
In addition, since the air that is heated while passing across the heater is supplied from the outer marginal portion of the cooking chamber to a central position where foodstuff is disposed, a considerable heat loss is created.
Moreover, since the conventional heat apparatus adopts the air convection method wherein air heated in the heater is circulated to heat foodstuff, the heating speed is low.
Furthermore, since the heat generated from the heater is transmitted to a peripheral device, resulting in damaging of the peripheral device, and since the heat generated from the heater is dispersed from the heater, its heating efficiency is degraded much more.
Therefore, an object of the present invention is to provide a heating apparatus of a microwave oven that is capable of improving heat efficiency by supplying air heated while passing across a heater to the center of a cooking chamber and rendering heat energy generated from the heater to be directly transmitted to a cooking object.
Another object of the present invention is to provide a heating apparatus of a microwave oven that is capable of reducing heat loss by increasing an amount of air which passes a heater by guiding air ventilated from a ventilating fan toward the heater and smoothing the air flow.
Still another object of the present invention is to provide a heating apparatus of a microwave oven that is capable of preventing heat energy generated from a heater from being transmitted to a peripheral device and reflecting the heat energy into a cooking chamber by installing a reflection plate at the heater.
To achieve these and other advantages, and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a heating apparatus of a microwave oven including: a heater installed at an upper portion of a cooking chamber into which foodstuff is received; a ventilating fan installed at one side of the heater, for circulating air inside the cooking chamber to pass across the heater; a panel having a suction hole installed at an upper portion of the cooking chamber, through which the air inside the cooking chamber is drawn into the ventilating fan, and a discharge hole, through which the air which has passed the heater is again supplied to the cooking chamber; and an air guide unit mounted at an upper side of the panel, for guiding air flow from the ventilating fan to the heater.
In the heating apparatus of a microwave oven of the present invention, the discharge hole for discharging heated air is formed at the center of the panel and the suction hole for sucking the air of the cooking chamber is formed at the marginal portion of the panel.
In the heating apparatus of a microwave oven of the present invention, the air guide unit includes an air guide formed to cover the heater, its lower side thereof being fixed at an upper face of the panel, and a fan housing formed to be connected to the air guide and cover the ventilating fan.
To achieve the above object, there is further provided a heating apparatus of a microwave oven including: a heater installed at an upper side of a cooking chamber into which foodstuff is received; a ventilating fan installed at one side of the heater, for circulating air inside a cooking chamber to pass across the heater; a panel having a suction hole installed at an upper side of the cooking chamber, through which the air of the cooking chamber is drawn into the ventilating fan and a discharge hole through which air which has passed across the heater is again supplied to the cooking chamber; and a reflecting plate disposed at the circumference of the heater, for preventing heat energy generated from the heater from being transmitted to a peripheral component, and reflecting the heat energy generated from the heater into the cooking chamber.
In the heating apparatus of a microwave oven of the present invention, the reflecting plate is disposed in the longitudinal direction of the heater and has a flange to be fixed at the panel formed at both ends thereof and a plurality of air passages for guiding air ventilated from the ventilating fan to the heater.
To achieve the above objects, there is also provided a heating apparatus of a microwave oven including: a heater installed at an upper side of a cooking chamber into which foodstuff is received; a ventilating fan installed at one side of the heater, for circulating air inside a cooking chamber to pass across the heater; a panel having a suction hole installed at an upper side of the cooking chamber, through which the air of the cooking chamber is drawn into the ventilating fan and a discharge hole through which air which has passed the heater is again supplied to the cooking chamber; an air guide unit mounted at an upper face of the panel, for guiding air flow from the ventilating fan to the heater; and a reflecting plate disposed at the circumference of the heater, for preventing heat energy generated from the heater from being transmitted to a peripheral component, and reflecting the heat energy generated from the heater into the cooking chamber.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.